This invention relates to a bending device such as an endoscope and a catheter.
Generally, an endoscope comprises a body, an insertion portion extending from the body, a bending portion extending from a distal end of the insertion portion, and a rigid portion provided at a distal end of the bending portion. The rigid portion has an inspection window and an illumination light window. The operator bends the bending portion to direct the rigid portion in a desired direction so as to observe a cavity in the body of the patient.
Bending mechanisms for bending a bending portion of such an endoscope are disclosed in U.S. Pat. No. 4,834,069 and Japanese Laid-Open (Kokai) patent application No. 121532/81. More specifically, a manipulation knob is mounted on the outside of a body, and the manipulation knob is connected to a pulley, mounted within the body, via a shaft extending through the body. Wires are fixedly connected at their proximal ends to the pulley. The wires extend through the bending portion and an insertion portion, and are fixedly connected at their distal ends to the distal end of the bending portion. When the pulley is angularly moved, one of the wires corresponding to this angular movement is pulled to bend the bending portion.
Japanese Utility Model Publication No. 52306/78 discloses a bending mechanism with a pulley and also a bending mechanism using a pinion and racks in mesh therewith, instead of a pulley. In the latter mechanism, the pinion is connected to a manipulation knob via a shaft, and wires are fixedly connected at their proximal ends to the racks, respectively.
The above conventional bending mechanisms employ either the manipulation knob and the pulley or the manipulation knob and the rack-and-pinion arrangement, and because of such a construction, the weight is increased. In addition, since either the pulley or the rack-and-pinion arrangement is mounted within the body, the body has an increased size. This results in a problem that the operator becomes fatigued relatively soon. Further, for operating such a bending mechanism, the operator holds the body with one hand, and angularly moves the manipulating knob with the fingers of this hand. This requires much skill.
U.S. Pat. No. 4,721,099 shows, in FIG. 17, a bending mechanism having a joy stick as an operating (manipulating) member. This bending mechanism has a drawback that a construction for supporting the joy stick is complicated, which increases the cost and the size of the body.
Japanese Laid-Open Utility Model application No. 163403/81 discloses an endoscope in which a rubber tube is fitted on a grip portion of a body.
There are U.S. patent application Ser. No. 407,314 filed on Sept. 14, 1989 now Pat. No. 4,944,455, and its West German counterpart (patent application No. P 3931719.6) disclosing a bending mechanism in which a wire-passing portion and a retainer portion for retaining a proximal end of a wire are provided within a body, and that of the wire disposed between the wire-passing portion and the retainer portion is pulled in the longitudinal direction of the wire.